Meet Grejo, pronounced grey-ho. He’s a Cuban land crab and our Jazz Cuba logo. His genus, Gecarcinus ruricola, is a species of terrestrial crab. Common names include the purple, black, red or yellow land crab, and sometimes zombie crab (because they raise their claws and stand defiantly when confronted by cars and foot falls). They reflect many colors and personalities just like Cubans.
Grejo (his moniker derives from cangrejo, Spanish word for crab) and his multitude thrive in untold millions in Cuba, and among the islands of the Caribbean.
We like him because he and his kind are plucky little devils. And jaunty just like the ebullient Cuban music and dance tours we organize. They move horizontally in edgy moonwalk way. Beyond these unruffled traits the life of Cuban land crab is an utterly fascinating natural history tale.
Each spring millions of small reddish land crabs emerge from the moist forests surrounding Cuba’s Bay of Pigs to breed in the nearby sea. As NATURE’s Cuba: Wild Island of the Caribbean shows, the evening invasions – which last for weeks – can wreak havoc on ordinary life. Roads become covered with smelly smashed crabs, while car owners must repair tires shredded by the sharp shells.
The crabs and their eggs do provide a feast for birds, fish, and some hungry mammals. But seafood-loving Cubans won’t touch them – they contain a harmful toxin.
More than four million years ago, the ancestor of these crabs – known to scientists as Gecarcoidea – lived in the sea. Slowly, however, they evolved to survive in a foreign place: the shady forest floor. But, like marine crabs, red land crabs still breathe with gills that must remain moist. To stay damp, the crabs dig tunnels. During the spring rains, males and females seek each other out and mate.
A few weeks later, the female crabs, swollen with eggs carried in a pouch, head for the nearby sea. The journey, which may be as long as six miles, can take days. And there are plenty of obstacles, such as roads, curbs, and even coastal resort swimming pools. On sunny days, the crabs must find shade – or dehydrate and die.
Those that reach the sea face one last challenge – laying their eggs while avoiding being swept back into the water. These crabs are true land creatures and cannot survive in the sea. Once the ripe eggs are successfully released into the water, they hatch immediately. After a few weeks, the baby crabs climb back onto land and head for the forests, to begin the cycle anew.
Officials make efforts to protect the crabs by closing some roads and sidewalks to create “crab crossings.” In part, that’s because the great crab migrations have become an unusual tourist draw. For some people, a glimpse of thousands of crabs scrambling into the surf is an unforgettable sight of a lifetime.
They grow one inch a year, mature in five, and live up to ten. They are nocturnal. They have a nephritic pad onto which they urinate. Microbes cleanse the pee then the precious moisture is reabsorbed. They can live many miles from the sea, and at high altitudes, but must return to the ocean to breed. They move swiftly, up to two yards a second.
Until age three, young crabs live in burrows dug by their elders and eat food brought to them adults. They are omnivorous scavengers and dine on dead plant and animal matter. A female lays around 85,000 eggs. Cars and trucks squish hundreds of thousands of land crabs when they cross roads during the annual mating march to the sea. Crab carcasses are a favorite snack for vultures, hawks and dogs – which have better road sense.